title: Opioid receptor types involved in the development of nicotine physical dependence in an invertebrate (Planaria) model.
abstract: Recent data suggest that opioid receptors are involved in the development of nicotine physical dependence in mammals. Evidence in support of a similar involvement in an invertebrate (Planaria) is presented using the selective opioid receptor antagonist naloxone, and the more receptor subtype-selective antagonists CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2) (μ, MOR), naltrindole (δ, DOR), and nor-BNI (norbinaltorphimine) (κ, KOR). Induction of physical dependence was achieved by 60-min pre-exposure of planarians to nicotine and was quantified by abstinence-induced withdrawal (reduction in spontaneous locomotor activity). Known MOR and DOR subtype-selective opioid receptor antagonists attenuated the withdrawal, as did the non-selective antagonist naloxone, but a KOR subtype-selective antagonist did not. An involvement of MOR and DOR, but not KOR, in the development of nicotine physical dependence or in abstinence-induced withdrawal was thus demonstrated in a sensitive and facile invertebrate model.
authors.affiliation: Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, PA, USA. Electronic address: robert.raffa@temple.edu.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Raffa
authors.forename: Steve
authors.initials: S
authors.lastname: Baron
authors.forename: Jaspreet S
authors.initials: JS
authors.lastname: Bhandal
authors.forename: Tevin
authors.initials: T
authors.lastname: Brown
authors.forename: Kevin
authors.initials: K
authors.lastname: Song
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Tallarida
authors.forename: Scott M
authors.initials: SM
authors.lastname: Rawls
mesh_terms: D000818:Animals; D008954:Models, Biological; D009538:Nicotine / Q000009:adverse effects*; D011957:Receptors, Opioid / Q000502:physiology*; D019966:Substance-Related Disorders
chemical_list: D011957:Receptors, Opioid; D009538:Nicotine
keywords: Abstinence; Nicotine; Opioid receptors; Physical dependence; Planaria; Withdrawal